Biomaterial Database

Integrin-linked kinase (ILK) binding to paxillin LD1 motif regulates ILK localization to focal adhesions. 2001

S N Nikolopoulos, and C E Turner

Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York 13210, USA.

Paxillin is a focal adhesion adapter protein involved in integrin signaling. Paxillin LD motifs bind several focal adhesion proteins including the focal adhesion kinase, vinculin, the Arf-GTPase-activating protein paxillin-kinase linker, and the newly identified actin-binding protein actopaxin. Microsequencing of peptides derived from a 50-kDa paxillin LD1 motif-binding protein revealed 100% identity with integrin-linked kinase (ILK)-1, a serine/threonine kinase that has been implicated in integrin, growth factor, and Wnt signaling pathways. Cloning of ILK from rat smooth muscle cells generated a cDNA that exhibited 99.6% identity at the amino acid level with human ILK-1. A monoclonal antibody raised against a region of the carboxyl terminus of ILK, which is identical in rat and human ILK-1 protein, recognized a 50-kDa protein in all cultured cells and tissues examined. Binding experiments showed that ILK binds directly to the paxillin LD1 motif in vitro. Co-immunoprecipitation from fibroblasts confirmed that the association between paxillin and ILK occurs in vivo in both adherent cells and cells in suspension. Immunofluorescence microscopy of fibroblasts demonstrated that endogenous ILK as well as transfected green fluorescent protein-ILK co-localizes with paxillin in focal adhesions. Analysis of the deduced amino acid sequence of ILK identified a paxillin-binding subdomain in the carboxyl terminus of ILK. In contrast to wild-type ILK, paxillin-binding subdomain mutants of ILK were unable to bind to the paxillin LD1 motif in vitro and failed to localize to focal adhesions. Thus, paxillin binding is necessary for efficient focal adhesion targeting of ILK and may therefore impact the role of ILK in integrin-mediated signal transduction events.

UI	MeSH Term	Description	Entries
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009130	Muscle, Smooth	Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)	Muscle, Involuntary,Smooth Muscle,Involuntary Muscle,Involuntary Muscles,Muscles, Involuntary,Muscles, Smooth,Smooth Muscles
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D010750	Phosphoproteins		Phosphoprotein
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D003598	Cytoskeletal Proteins	Major constituent of the cytoskeleton found in the cytoplasm of eukaryotic cells. They form a flexible framework for the cell, provide attachment points for organelles and formed bodies, and make communication between parts of the cell possible.	Proteins, Cytoskeletal
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia